EP0856502A2 - Stable form of iron humate or of other meso and micro nutritive elements available for plant nutrition and method for obtaining it - Google Patents

Stable form of iron humate or of other meso and micro nutritive elements available for plant nutrition and method for obtaining it Download PDF

Info

Publication number
EP0856502A2
EP0856502A2 EP98830045A EP98830045A EP0856502A2 EP 0856502 A2 EP0856502 A2 EP 0856502A2 EP 98830045 A EP98830045 A EP 98830045A EP 98830045 A EP98830045 A EP 98830045A EP 0856502 A2 EP0856502 A2 EP 0856502A2
Authority
EP
European Patent Office
Prior art keywords
humic
iron
humic substances
metal
substances
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP98830045A
Other languages
German (de)
French (fr)
Other versions
EP0856502A3 (en
EP0856502B1 (en
Inventor
Paolo Sequi
Marco Govi
Claudio Ciavatta
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Valagro SpA
Original Assignee
Valagro SpA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Valagro SpA filed Critical Valagro SpA
Publication of EP0856502A2 publication Critical patent/EP0856502A2/en
Publication of EP0856502A3 publication Critical patent/EP0856502A3/en
Application granted granted Critical
Publication of EP0856502B1 publication Critical patent/EP0856502B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C05—FERTILISERS; MANUFACTURE THEREOF
    • C05B—PHOSPHATIC FERTILISERS
    • C05B13/00—Fertilisers produced by pyrogenic processes from phosphatic materials
    • C05B13/06—Alkali and alkaline earth meta- or polyphosphate fertilisers
    • C—CHEMISTRY; METALLURGY
    • C05—FERTILISERS; MANUFACTURE THEREOF
    • C05D—INORGANIC FERTILISERS NOT COVERED BY SUBCLASSES C05B, C05C; FERTILISERS PRODUCING CARBON DIOXIDE
    • C05D9/00—Other inorganic fertilisers
    • C05D9/02—Other inorganic fertilisers containing trace elements

Definitions

  • the soil often contains abundant quantities of these elements, but most ofthem may be present in insoluble forms, such as oxides (for instance Fe 2 O 3 ), hydroxides (for instance Fe(OH) 3 ) and carbonates (for instance CaCO 3 and MgCO 3 ), not available for vegetable nutrition since they are found in an insoluble crystalline or amorphous form.
  • oxides for instance Fe 2 O 3
  • hydroxides for instance Fe(OH) 3
  • carbonates for instance CaCO 3 and MgCO 3
  • a gaseous phase a liquid phase and a solid phase
  • the last one comprises a mineral part and organic materials.
  • Organic materials in turn comprise humic substances and non humified substances, and they derive from the contribution and from the transformation of animal and vegetable organic residues.
  • Humic substances are of a complex polymeric nature and they possess numerous functional groups, prevalently carboxylic and phenolic; they are very stable over time, difficult for micro-organisms to attack and able to perform a series of agronomic functions maintaining a certain level of fertility in the soil.
  • the nutritional functions of humic substances are:
  • said indirect nutritional function is considered the more important one to make available different metallic nutritive elements, such as iron, calcium and magnesium.
  • Humic substances tend to chelate the metals present in the soil solution, thus preventing their precipitation in the form of oxides, hydroxides or carbonates, unusable because they are in insoluble forms, inaccessible to the roots of the plants. Said chelation, instead, makes the metals available for nutritional processes.
  • Fertilisation can essentially be performed in two ways: through the leaves or through the soil. In foliar fertilisation the fertiliser is absorbed through the tissues that coat the outer part of the leaves, so it can only take place with fertilisers whose molecular structure has very small dimensions and this vehicle is used mostly to solve momentary problems of nutritional deficiency. Different is the case of fertilisation through the soil, which is the means that ensures plant nutrition in nature.
  • the field of the present invention covers the fertilisation that takes place through the soil, the latter being meant as the natural means to make the fertiliser available to the root apparatus.
  • the fertiliser constituted by a common salt, for instance ferrous sulfate (FeSO 4 ) placed in a soil lacking iron, with a neutral-alkaline pH (e.g. pH 7-8) and poor in humic substances, from transforming itself into insoluble products such as oxide, hydroxide and carbonate.
  • a common salt for instance ferrous sulfate (FeSO 4 ) placed in a soil lacking iron, with a neutral-alkaline pH (e.g. pH 7-8) and poor in humic substances
  • a fertiliser based on meso and micro elements to be used for soil fertilisation should have the following characteristics:
  • humic substances corresponds to the characteristics required by an ideal chelating-complexing agent.
  • humic substances are in any case the ideal complexing agents for iron and for the other nutritive elements, as is known from the technical literature, for example according to F.J. Stevenson “Humus Chemistry” J.Wiley & Sons Ed. (1982), according to P. Sequi "La sostanza organica nel terreno. Funzioni nutnzionali” L'Italia agricola 113(2):91-112 (1976).
  • the structure of the humic substances is not well defined in the part the involves the chelation of metals. It is however known that the humic molecule uses mainly the OHs of the functional groups to be able to complex the metal elements (Stevenson, 1982). According to some authors the structure of the metal-humate complex involves two oxyhydrils, one of them carboxylic and one deriving from another functional group, alcoholic, phenolic or other. As reported by Sequi (1976), the structure of the complex also comprises a phosphate group that in this case has two functions:
  • the extraction of the humic substances using a base such as NaOH or KOH takes place through the salification of the humic and fulvic acids in an alkaline environment according to the following reaction: HA-OH + K-OH ⁇ HA-OK + H 2 O where HA-OH is the humic acid.
  • the K + can also be replaced with Na + ; the compound that is formed (HA-OK or HA-ONa) is a salt of the humic acid (humate).
  • the base alone is not able to salify the humic acid and the extraction of the humic acid complexed with the metal has to take place with the aid of a salt that possesses a chelating agent, such as sodium or potassium pyrophosphate.
  • a salt that possesses a chelating agent such as sodium or potassium pyrophosphate.
  • the metal would be detached from the humic acid and replaced with the K - , thereby originating a salt of the humic acid, whilst the metal would be complexed by the pyrophosphate originating an insoluble salt which would precipitate ( ).
  • the aforesaid reaction is likely to take place only if the complexing agent of the iron has a bonding force weaker than that of the pyrophosphate, but it cannot take place when the organic complexing agent (humic substance in the specific case) has a bonding force stronger than that of the inorganic complexing agent (pyrophosphate).
  • the humic substances that are used as raw materials are already in extracted form (for example humic extracts obtained by extraction with KOH of the humic substances from leonardite) and therefore one is faced with potassic salts of organic acids. This is obviously a very complex mixture wherein are present both compounds with low and with high chelating force.
  • the productive method constituting the subject of the presence invention comprises the following steps:
  • salts of organic compounds are not to be used, since one would not be certain of said chelating/complexing reactions on the part of the humic substances, but one would risk obtaining a mixture of humic substances and of the metal complex, which presents the problems described above.
  • a soluble complex is formed between the humic substances, the metal and the pyrophosphate, stable enough to be dehydrated (dehydration must take place immediately after the preparation phase).
  • the dehydrated product can be completely redissolved in water and can thus be used for soil fertilisation with the practice of ferti-irrigation.
  • the final product has a total iron content, completely bonded to the humic substances, equal to or greater than 3 ⁇ 4% depending on the organic matrix used for the extraction of the humic substances. Using optimal humic extracts, it is possible to obtain an iron humate containing about 4.5% of chelated iron.
  • Said titre can turn out to be lower if one uses organic extracts from peats, compost or other organic matrices less humified than leonardite. With some humic extracts from coal dusts a titre was obtained equal to 7% in bonded iron. If metals having different atomic weight and valence from iron are used, it is obvious that the titres in metal complexed with the humic substances will be different. The main reason why in most cases reference is made to iron is that this nutritive element is, without a doubt, the most critical one in meso and microelement nutritional deficiencies.
  • the quantities of reactants must be perfectly calibrated in order to avoid adding an excess of metal and thereby causing the precipitation of Fe-pyrophosphate and/or humic substances polymerised around iron.
  • the iron humates prepared until now were characterised, at a neutral to alkaline pH value, by a structure similar to the following one:
  • the product obtained was subjected on an iron-poor soil, in a controlled environment, to agronomic tests in comparison with other classic chelates (EDDHA-Fe) and the following results were obtained: all horticultural plants tested (cucumbers, strawberries, etc.) yielded sharply better productive results from the quantitative and qualitative point of view when they were fertilised with iron humate, whereas the other classic chelates yielded positive results that were temporary and discontinuous.
  • EDDHA-Fe classic chelates
  • Example I Numerous variations exist to Example I reported above since the humic extracts can come from different sources and thus can be obtained with a variety of solvents, at different pressures and temperatures, and come from all the organic matrices containing humic substances or the like (e.g. peats, lignites, leonardites, coals, organic manures, compost, sludges, sewage, soil, etc.).
  • organic matrices containing humic substances or the like e.g. peats, lignites, leonardites, coals, organic manures, compost, sludges, sewage, soil, etc.
  • the method can also be applied to the salts of other metals essential for plant nutrition such as calcium, magnesium, zinc, etc.
  • pyrophosphates and metaphosphates can be used, as well as pyrophosphoric and metaphosphoric acid and all organic and inorganic compounds containing phosphorus, provided the reaction is regulated with buffering systems.
  • a fruit orchard comprising twenty rows of pear trees suffering from iron and zinc deficiency was fertilised, in groups of four rows, in the first row with a product identical to the one described in Example I, in the second row with a product that was wholly similar, except for the preparation conducted with zinc sulfate instead of iron sulfate, in the third row with a mixture ofthe two previous ones, whilst in the fourth row fertilisation was omitted. Each subsequent group of four rows was fertilised for confirmation according to the same procedures.
  • Trees in some rows of an orange orchard planted on highly calcareous and iron-poor soil were alternatively fertilised or not with a product identical to that of Example I, except for the preparation, which had been conducted with sodium metaphosphate instead of potassium pyrophosphate.
  • the tests yielded excellent qualitative and quantitative results only in the fertilised trees. The positive results were confirmed for four years after fertilisation.

Abstract

Described herein is a complex between humic substances and iron denominated "iron humate" characterised in that it has a structure of the type:
Figure 80000001
where the metal is protected from the pyrophosphate and from the humic substances (SU), obtained through a method comprising the following phases:
  • a) dosage of the humic extracts
  • b) purification of said humic extracts through centrifuging or filter pressing to eliminate any suspended particles
  • c) transfer of the floating product into a mixer
  • d) preparation of a solution of K4P2O710H2O
  • e) mixing solution d) with an aqueous solution of FeSO47H2O containing a minimum quantity of H2SO4 operating slowly and keeping the humic extract under vigorous agitation
  • f) after agitation for a few minutes, rapid drying at 60-90°C.
    •

    Description

    It is known that the meso and micro elements essential for plant nutrition are fundamentally calcium, magnesium, sulphur, iron, manganese, copper, zinc, boron and molybdenum. Under agricultural conditions, situations of nutritional deficiency may arise mainly due to an insufficient availability of iron, calcium and magnesium and at times also of the other elements.
    In reality, the soil often contains abundant quantities of these elements, but most ofthem may be present in insoluble forms, such as oxides (for instance Fe2O3), hydroxides (for instance Fe(OH)3) and carbonates (for instance CaCO3 and MgCO3), not available for vegetable nutrition since they are found in an insoluble crystalline or amorphous form.
    There are only few vegetable species which, in case of need dictated by the absence of more easily available forms, are able to set in motion an effective, but costly biochemical process that allows to bring back to a soluble form precipitated elements in the form of oxides, hydroxides or carbonates. The mechanisms illustrated in the example can apply, in addition to iron, calcium and magnesium, also for manganese, copper and zinc. All these nutritive elements shall therefore have to be present in the soil in a form available for their assimilation, in order to be used by plants.
    Different physical phases are present in the soil: a gaseous phase, a liquid phase and a solid phase; the last one comprises a mineral part and organic materials.
    Organic materials in turn comprise humic substances and non humified substances, and they derive from the contribution and from the transformation of animal and vegetable organic residues. Humic substances are of a complex polymeric nature and they possess numerous functional groups, prevalently carboxylic and phenolic; they are very stable over time, difficult for micro-organisms to attack and able to perform a series of agronomic functions maintaining a certain level of fertility in the soil.
    The nutritional functions of humic substances are:
  • 1) direct, when the nutritive elements are released in the course of the slow mineralisation of the humic substances themselves;
  • 2) indirect, when for instance their ability to complex and chelate the metals that are found in the liquid phase, then to cede them to the plants, is used.
    • In nature said indirect nutritional function is considered the more important one to make available different metallic nutritive elements, such as iron, calcium and magnesium. Humic substances tend to chelate the metals present in the soil solution, thus preventing their precipitation in the form of oxides, hydroxides or carbonates, unusable because they are in insoluble forms, inaccessible to the roots of the plants. Said chelation, instead, makes the metals available for nutritional processes. Fertilisation can essentially be performed in two ways: through the leaves or through the soil. In foliar fertilisation the fertiliser is absorbed through the tissues that coat the outer part of the leaves, so it can only take place with fertilisers whose molecular structure has very small dimensions and this vehicle is used mostly to solve momentary problems of nutritional deficiency. Different is the case of fertilisation through the soil, which is the means that ensures plant nutrition in nature.
    The field of the present invention covers the fertilisation that takes place through the soil, the latter being meant as the natural means to make the fertiliser available to the root apparatus. Thus it entails preventing the fertiliser, constituted by a common salt, for instance ferrous sulfate (FeSO4) placed in a soil lacking iron, with a neutral-alkaline pH (e.g. pH 7-8) and poor in humic substances, from transforming itself into insoluble products such as oxide, hydroxide and carbonate.
    From an ideal point of view, a fertiliser based on meso and micro elements to be used for soil fertilisation should have the following characteristics:
  • 1) have the metal bonded in a form that can be assimilated, i.e. transformed, where it is not originally, into a soluble form and hence available for root nutrition;
  • 2) have a sufficient bond force not to lose the metal in the soil, but not excessive to allow the chelating agents of the roots to detach it and make it available for the biochemical processes employed for absorption by the vegetables;
  • 3) not be easily degradable in the soil to be able to maintain the metal in chelated form for a long enough time, corresponding at least to the entire cultivation cycle. Currently there are three main categories of fertilisers based on meso and micro elements:
  • a) Inorganic salts, which lack the ability to make the fertilising element available for the roots for a sufficiently long period;
  • b) Organic complexes, which are essentially organic salts with functional groups (e.g. citric acid) able to bond a metal even strongly.
    • Said complexes very often do not allow a good utilisation of the metal both due to biodegradability through micro-organism attack, and due to the excessively intense bond force, which does not allow the metal to be freed and inserted in the biological cycles;
    • c) Organic chelates which are characterised by complexing the metal with multiple co-ordination bonds on the part of polyvalent molecules which in this way envelop it protecting it with a configuration which can be depicted as a pincer, or chela. The structure of these compounds is thus such as to offer a sufficient protection to the metal, maintaining it in available form for a sufficiently long time. This means that in theory a contribution of fertiliser through an organic chelate is able to meet the requirement of a cultivation for a sufficiently long time. These types of chelates, however, do not escape from microbic activity and thus undergo a rather rapid degradation, such as not to allow the availability of the metal in the soil through the entire cultivation season. It is therefore possible that in that case the cultivated plants live for a period of the year in a phase of nutritional deficiency, particularly if they are pluriennial species (for instance fruit bearing plants).
    The possibility is known of using as organic salts some derivatives of the tartronic acids and their salts in the variants with and without phosphate mobilisation, as Italian patents no. 767605, no. 788509 and no 833128 teach. Other chelates and organic salts are described in US patents 4.181.516 (Gray, 1980) and 4.786.387 (Marihart, 1988) and in European patent 284339 B1 (Marihart, 1991). In these last two patents fulvic acid (a fraction of the humic substances) is used together with various chelates and anhydrous ammonia (in order to neutralise the mixture) without obtaining the formation of protective bridge structures of the type that is the subject of the present invention.
    A work published by D.F. Clemens and colleagues in Fertilizer Research Vol 25, pp. 127-131(1990) describes the structure of chelating agents and of the related metal complexes, such as those of Fe(III), distinguishing it in two classes: aminopolycarboxylates and hydroxycarboxylates (where the term carboxylate means "functional group of an organic acid"). For instance to the aminopolycarboxylate class belong EDTA (ethylendiamintetracetic acid), and also EDDHA (ethylendiamine di(o-hydroxyphenylacetic) acid); to the hydroxycarboxylic class belong, for instance citric acid, gluconic acid, glucoheptonic acid.
    The structure of the humic substances corresponds to the characteristics required by an ideal chelating-complexing agent. For the purposes of vegetable nutrition, humic substances are in any case the ideal complexing agents for iron and for the other nutritive elements, as is known from the technical literature, for example according to F.J. Stevenson "Humus Chemistry" J.Wiley & Sons Ed. (1982), according to P. Sequi "La sostanza organica nel terreno. Funzioni nutnzionali" L'Italia agricola 113(2):91-112 (1976).
    The structure of the humic substances is not well defined in the part the involves the chelation of metals. It is however known that the humic molecule uses mainly the OHs of the functional groups to be able to complex the metal elements (Stevenson, 1982). According to some authors the structure of the metal-humate complex involves two oxyhydrils, one of them carboxylic and one deriving from another functional group, alcoholic, phenolic or other. As reported by Sequi (1976), the structure of the complex also comprises a phosphate group that in this case has two functions:
  • 1) to protect the metal (for instance, iron) from being completely "enclosed" by the humic substances, thereby becoming less easily available for plants and
  • 2) to be available in turn as such for vegetable nutrition.
    • In this respect it should not be forgotten that phosphate also presents great problems of availability in the soil since it is easily prone to undergo precipitation processes.
    According to Stevenson (1982), the extraction of the humic substances using a base such as NaOH or KOH takes place through the salification of the humic and fulvic acids in an alkaline environment according to the following reaction: HA-OH + K-OH → HA-OK + H2O where HA-OH is the humic acid. The K+ can also be replaced with Na+; the compound that is formed (HA-OK or HA-ONa) is a salt of the humic acid (humate).
    In the case wherein to the humic molecule is bonded a non alkaline metal (e.g. iron), the base alone is not able to salify the humic acid and the extraction of the humic acid complexed with the metal has to take place with the aid of a salt that possesses a chelating agent, such as sodium or potassium pyrophosphate. According to what is reported by Stevenson (1982) the reaction that would take the humic acid into solution could be as follows:
    Figure 00070001
    In other words the metal would be detached from the humic acid and replaced with the K-, thereby originating a salt of the humic acid, whilst the metal would be complexed by the pyrophosphate originating an insoluble salt which would precipitate (
    Figure 00070002
    ).
    The aforesaid reaction is likely to take place only if the complexing agent of the iron has a bonding force weaker than that of the pyrophosphate, but it cannot take place when the organic complexing agent (humic substance in the specific case) has a bonding force stronger than that of the inorganic complexing agent (pyrophosphate).
    In a process of extraction of the humic substances, i.e. of solubilisation, the combined action of the two extracting agents KOH and K4P2O7 allows to realise the following phases (Stevenson, 1982; E. Bar-Ness and Y. Chen Plant Soil, 130, 35-43, 1991):
  • 1) solubilisation by the KOH, in the form of potassic salts, of the humic substances not complexed to metals;
  • 2) solubilisation by the K4P2O7 in the form of potassic salts, of the humic substances bonded to metals with low chelating force with simultaneous precipitation of the metal-pyrophosphate complexes;
  • 3) solubilisation by the K4P2O7 of the humic substances bonded to metals with high chelating force with the formation of a complex between the humic substance and the pyrophosphate by means of a metal bridge. This phase is confirmed by Stevenson (1982) when he described the extraction (solubilisation) criteria of copper from the soil: the form bonded to the organic substance is extracted with pyrophosphate. The same reaction is described in the work by Bar-Ness and Chen (1991), when they discuss a remarkable presence of iron in the organic substance extracted from a peat previously complexed with iron.
    • In the occasions mentioned above and in other cases wherein the attempt was made to prepare metal chelates based on humic substances for research or commercial purposes, in order to have available a product with higher quality and performance than those of the products present on the market, the following problems were noted:
    • in many cases, mainly because of erroneous stoichiometric computations, the addition of the metal to the humic extract (saline aqueous solution containing the humic substances in solubilised form) led to an immediate flocculation of the extract;
    • the chelates based on humic substances prepared until now were in the liquid state, in the form of a solution, but the solubility of the product was very low due to the polymerisation phenomena that took place in a few days: only the complexes of the metals with the fulvic acids (US Patent 4.786.387 and European patent 284.339) could be soluble for the presence of other chelating substances as has been stated above:
    • the quantity of metal bonded to the humic substances was always very low and not sufficient to justify the launch on the market of a commercial formulation (Lobartini and Orioli, Plant Soil, 106, 153, 1988);
    • the products were not found to be soluble after drying; this highlighted the fact that the presence of the metal had favoured the formation of a closed polymer and hence of a flocculate.
    Said problems and others presented by the known techniques and products are solved by the present invention which describes a stable composition of iron humate or other meso and micro nutritive elements available for vegetable nutrition and the method for obtaining it.
    In the case of the present invention the humic substances that are used as raw materials are already in extracted form (for example humic extracts obtained by extraction with KOH of the humic substances from leonardite) and therefore one is faced with potassic salts of organic acids. This is obviously a very complex mixture wherein are present both compounds with low and with high chelating force.
    The productive method constituting the subject of the presence invention comprises the following steps:
  • a) To the humic extract obtained through the solubilisation of humic substances with an aqueous solution of KOH or other alkaline reactant, after the accurate elimination by centrifuging or filter pressing of the parts which may be in suspension, is added a quantity, to be defined according to the characteristics of the humic extract, of a molecule of the pyrophosphate type (K4P2O7). In this phase all that is done is to mix the components without provoking any specific reaction.
  • b) To the solution obtained in phase a), slowly in order to make possible the chelation/complexing reaction, but immediately, is added a solution of FeSO4 or other inorganic salt completely soluble in water. If the salt is said ferrous sulfate, at this point the iron, the humic substance and the K4P2O7 react to each other according to the mechanism described below: the humic substance contained in the extract can have very different complexing forces, but for the purposes of the reaction mechanism with the Fe(II) and with the K4P2O7we are interested in subdividing them in to categories: 1) humic substances with chelating force greater than that of K4P2O7 and 2) humic substances with chelating force smaller than K4P2O7. In the moment wherein an Fe(II) ion is added to the solution containing the humic substances in potassic form and the K4P2O7, the metal is complexed by the humic molecule with the greatest chelating force and simultaneously it forms a bridge with a phosphate of the K4P2O7 forming a phospho-metal-humate complex. The evidence of this reaction is given by the fact that, if the metal bonded only to the K4P2O7 a light coloured precipitate would be formed, whereas if a reaction took place only between the humic substance and the iron, there would be flocculation of the humic substance with the subsequent formation of a dark precipitate. Said reaction takes place until all the humic substances with chelating force greater than that of the K4P2O7 have reacted with the iron and thus also with the K4P2O7. At this point, if Fe(II) is continued to be added it has been observed that the metal is complexed by the K4P2O7 because the latter is now the free complexing agent with the greatest bonding force. As further evidence of this one can observe the immediate formation of a whitish flocculate.
    • In the method constituting the subject of the present invention, salts of organic compounds are not to be used, since one would not be certain of said chelating/complexing reactions on the part of the humic substances, but one would risk obtaining a mixture of humic substances and of the metal complex, which presents the problems described above.
    With the method of the present invention a soluble complex is formed between the humic substances, the metal and the pyrophosphate, stable enough to be dehydrated (dehydration must take place immediately after the preparation phase). The dehydrated product can be completely redissolved in water and can thus be used for soil fertilisation with the practice of ferti-irrigation. The final product has a total iron content, completely bonded to the humic substances, equal to or greater than 3÷4% depending on the organic matrix used for the extraction of the humic substances. Using optimal humic extracts, it is possible to obtain an iron humate containing about 4.5% of chelated iron. Said titre can turn out to be lower if one uses organic extracts from peats, compost or other organic matrices less humified than leonardite. With some humic extracts from coal dusts a titre was obtained equal to 7% in bonded iron. If metals having different atomic weight and valence from iron are used, it is obvious that the titres in metal complexed with the humic substances will be different. The main reason why in most cases reference is made to iron is that this nutritive element is, without a doubt, the most critical one in meso and microelement nutritional deficiencies.
    The quantities of reactants must be perfectly calibrated in order to avoid adding an excess of metal and thereby causing the precipitation of Fe-pyrophosphate and/or humic substances polymerised around iron.
    The iron humates prepared until now were characterised, at a neutral to alkaline pH value, by a structure similar to the following one:
    Figure 00110001
    In this situation the metal ion, in spite of the alkalinity of the medium, causes the rapid polymerisation of the humic substances forming a complex of the type:
    Figure 00120001
    Polymerisation could be prevented only by drastically reducing the bivalent metal (Fe) content, in order to entrust potassium, as the counter ion, with the task of keeping the complex in solution. In other words the potassium ion must neutralise most of the charges of the functional groups of the humic substances preventing polymerisation by the iron. On the basis of what has been stated and of available information it is deemed that the iron humate is, from a chemical point of view, thus formed:
    Figure 00120002
    With such a structure the metal is protected from the pyrophosphate and from the humic substances and the rapid flocculation of the complex due to the creation of possible co-ordination bonds is prevented.
    To obtain the products constituting the subject of the present invention the following methods are reported below, purely by way of non limiting examples:
    Example I
    The following phases were realised:
  • a) the humic extracts were dosed to correspond to kg 3 of dehydrated humic extracts;
  • b) said humic extracts were purified of suspended particles (clay substances and colloidal organic material in suspension), through centrifuging;
  • c) the floating product was transferred into a mixer;
  • d) a quantity of kg 1.5 of K4P2O710H2O was added into the mixer and dissolved completely;
  • e) separately, an aqueous solution is prepared of kg 1 of FeSO47H2O in 10÷15 litres of water, with the addition of a minimum quantity of H2SO4 to prevent the oxidation of the Fe(II) to Fe(III);
  • f) to the completed solution d) was slowly added solution e), simultaneously and rapidly agitating the humic extract;
  • g) agitation was protracted for 5 minutes and then drying was rapidly performed.
    • Overall, kg 4.5 of finished products were obtained with a bonded iron titre equal to 4.4%.
    The product obtained was subjected on an iron-poor soil, in a controlled environment, to agronomic tests in comparison with other classic chelates (EDDHA-Fe) and the following results were obtained:
    all horticultural plants tested (cucumbers, strawberries, etc.) yielded sharply better productive results from the quantitative and qualitative point of view when they were fertilised with iron humate, whereas the other classic chelates yielded positive results that were temporary and discontinuous.
    The above results demonstrate the greater fertilising efficiency of the present invention, compared with products normally used today for plant nutrition.
    Numerous variations exist to Example I reported above since the humic extracts can come from different sources and thus can be obtained with a variety of solvents, at different pressures and temperatures, and come from all the organic matrices containing humic substances or the like (e.g. peats, lignites, leonardites, coals, organic manures, compost, sludges, sewage, soil, etc.).
    In addition to iron salts, the method can also be applied to the salts of other metals essential for plant nutrition such as calcium, magnesium, zinc, etc.
    In addition to decahydrate tetrapotassic pyrophosphate, other types of pyrophosphates and metaphosphates can be used, as well as pyrophosphoric and metaphosphoric acid and all organic and inorganic compounds containing phosphorus, provided the reaction is regulated with buffering systems.
    Example II
    A fruit orchard comprising twenty rows of pear trees suffering from iron and zinc deficiency was fertilised, in groups of four rows, in the first row with a product identical to the one described in Example I, in the second row with a product that was wholly similar, except for the preparation conducted with zinc sulfate instead of iron sulfate, in the third row with a mixture ofthe two previous ones, whilst in the fourth row fertilisation was omitted. Each subsequent group of four rows was fertilised for confirmation according to the same procedures.
    Production sharply improved in the first and second row of each group, but only in the third one did it become abundant and qualitatively perfect. The trees of the fourth row deteriorated and their production appeared extremely poor. During the five years following that of fertilisation the trees of the third row continued to show full vegetative and productive vigour, whilst those of the first and of the second row progressively decreased their production and some of the trees of the fourth row even died, with subsequent failures along the row.
    Example III
    Trees in some rows of an orange orchard planted on highly calcareous and iron-poor soil were alternatively fertilised or not with a product identical to that of Example I, except for the preparation, which had been conducted with sodium metaphosphate instead of potassium pyrophosphate. The tests yielded excellent qualitative and quantitative results only in the fertilised trees. The positive results were confirmed for four years after fertilisation.
    The invention thus conceived can be subject to numerous modifications and variations, without thereby departing from the scope of the inventive concept.
    In practice, modifications and/or improvements are possible without thereby departing from the scope of the claims that follows.

    Claims (5)

    1. Humic complex denominated "iron humate" having a structure of the type:
      Figure 00160001
      where the metal is protected from the pyrophosphate and from the humic substances (SU), obtained through a method characterised in that it comprises the following phases:
      a) dosage of the humic extracts
      b) purification of said humic extracts through centrifuging or filter pressing to eliminate any suspended particles
      c) transfer of the floating product into a mixer
      d) preparation of a solution of K4P2O710H2O
      e) mixing solution d) with an aqueous solution of FeSO47H2O containing a minimum quantity of H2SO4 operating slowly and keeping the humic extract under vigorous agitation
      f) after agitation for a few minutes, rapid drying.
    2. Product obtained with the method according to claim 1, characterised in that it has a structure of the type:
      Figure 00170001
    3. Product obtained with the method according to claim 1, characterised in that it contains as metals, instead of iron, calcium, magnesium, manganese, copper, zinc, cobalt, and any element useful for vegetable nutrition, in their different states of oxidation.
    4. Product obtained according to the methods described in the previous claims, characterised in that it has employed, in the course of the preparation, molecules other than pyrophosphate, but able to form bridges with the iron or with the other metals which in turn are bonded to the humic substances.
    5. Product obtained according to one of the methods described in the previous claims, characterised in that it contains artificial humic substances, or fractions of natural or artificial humic substances, soluble or insoluble.
    EP98830045A 1997-02-03 1998-01-30 Stable form of iron humate or of other meso and micro nutritive elements available for plant nutrition and method for obtaining it Expired - Lifetime EP0856502B1 (en)

    Applications Claiming Priority (2)

    Application Number Priority Date Filing Date Title
    IT97RM000053A IT1290913B1 (en) 1997-02-03 1997-02-03 STABLE FORM OF IRON HUMATE OR OTHER MESO AND MICRO NUTRITIONAL ELEMENTS AVAILABLE FOR PLANT NUTRITION AND METHOD FOR
    ITRM970053 1997-02-03

    Publications (3)

    Publication Number Publication Date
    EP0856502A2 true EP0856502A2 (en) 1998-08-05
    EP0856502A3 EP0856502A3 (en) 1999-04-14
    EP0856502B1 EP0856502B1 (en) 2002-09-04

    Family

    ID=11404711

    Family Applications (1)

    Application Number Title Priority Date Filing Date
    EP98830045A Expired - Lifetime EP0856502B1 (en) 1997-02-03 1998-01-30 Stable form of iron humate or of other meso and micro nutritive elements available for plant nutrition and method for obtaining it

    Country Status (5)

    Country Link
    US (1) US6080220A (en)
    EP (1) EP0856502B1 (en)
    ES (1) ES2182256T3 (en)
    HU (1) HUP9800188A3 (en)
    IT (1) IT1290913B1 (en)

    Cited By (4)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    FR2803290A1 (en) * 1999-12-29 2001-07-06 Serge Allegre Production of a composition for correcting metal deficiencies in plants, e.g. chlorosis, comprises mixing an organic material with at least one metal salt and composting the mixture
    EP1103535A3 (en) * 1999-11-24 2001-11-21 Iwao Takeda Fertilizer containing polyphosphate-metal chelates
    DE102005061117A1 (en) * 2005-12-19 2007-06-21 Tilco Biochemie Gmbh Preparation for soil improvement and fertilization
    EP3208254A1 (en) * 2016-02-17 2017-08-23 Fertinagro Nutrientes, S.L. Fertilizing composition which includes ions complexed with humic substances to improve the biological fixation of nitrogen by microorganisms present in the soil

    Families Citing this family (17)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    GB9623578D0 (en) * 1996-11-13 1997-01-08 Univ Leeds Synthetic sesquioxide biomass conditioning and preservation process
    US6911415B1 (en) 2001-06-09 2005-06-28 Actagro, Llc Fungicidal compositions containing organic compositions derived from natural organic materials, phosphorous acid, phosphite salts and phosphate salts, methods of making same and methods of applying same to plants
    DE10351274A1 (en) * 2003-10-31 2005-06-02 Humintech Gmbh Metal compound of humic acids, their preparation, compositions containing them and use thereof
    US7825266B1 (en) * 2004-06-15 2010-11-02 Mcmahon Geoff Extraction of fulvic minerals from humic substances
    CA2530230A1 (en) * 2004-12-15 2006-06-15 Bioz Agri Products Inc. Sprayable organic fertilizer
    US8383840B1 (en) 2005-06-15 2013-02-26 Geoff McMahon Extraction of fulvic minerals, vitamins, amino acids, enzymes, and phytonutrients from humic substances
    ES2335562B2 (en) 2007-03-07 2011-11-30 Timac Agro España, S.A. HETEROMOLECULAR METALIC COMPLEXES (CHELATES) OF HUMAN NATURE.
    WO2010006233A2 (en) * 2008-07-11 2010-01-14 Floratine Biosciences, Inc. Foliarly applicable silicon nutrition compositions & methods
    DK2473034T3 (en) * 2009-09-03 2021-02-08 Fbsciences Holdings Inc Seed treatment compositions and method
    EP2482638A4 (en) * 2009-09-28 2013-08-07 Fbsciences Holdings Inc Methods of reducing plant stress
    EP2483221A4 (en) * 2009-09-28 2015-05-13 Fbsciences Holdings Inc Fertilizer compositions and methods
    US20110237438A1 (en) * 2010-03-29 2011-09-29 Marihart John R Extraction of organic matter from naturally occurring substrates
    CA2805115A1 (en) 2010-07-15 2012-01-19 Fbsciences Holdings, Inc. Microorganism compositions and methods
    US8685133B2 (en) 2010-12-22 2014-04-01 Scott G. Williams, Llc Chelated compositions and methods of making and using the same
    US8784665B1 (en) 2011-04-12 2014-07-22 Geoff McMahon Method for reducing odor and harmful materials from sewer plant process streams
    AU2013207818B2 (en) 2012-01-12 2017-02-02 Fbsciences Holdings, Inc. Modulation of plant biology
    AR119664A1 (en) 2018-11-07 2022-01-05 Compass Minerals Usa Inc POTASSIUM SULFATE CONVERSION PROCESS TO POTASSIUM HYDROGEN SULFATE

    Citations (4)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    DE1247351B (en) * 1959-03-06 1967-08-17 Hokkaido Tanko Kisen Kabushiki Process for the production of granulated, humus-containing phosphate fertilizers
    FR2234245A1 (en) * 1973-06-25 1975-01-17 Rodrigues Correia Zulmdra Humic acid fertilisers - prepd. by oxidn. of organic material and treatment with alkali and phosphate
    EP0282250A2 (en) * 1987-03-09 1988-09-14 American Colloid Company Liquid crop stimulant
    US5354350A (en) * 1993-12-14 1994-10-11 The Vigoro Corporation Citrate soluble slow release iron humate

    Family Cites Families (1)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    JPS606318B2 (en) * 1979-12-13 1985-02-16 日本重化学工業株式会社 mixed phosphate fertilizer

    Patent Citations (4)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    DE1247351B (en) * 1959-03-06 1967-08-17 Hokkaido Tanko Kisen Kabushiki Process for the production of granulated, humus-containing phosphate fertilizers
    FR2234245A1 (en) * 1973-06-25 1975-01-17 Rodrigues Correia Zulmdra Humic acid fertilisers - prepd. by oxidn. of organic material and treatment with alkali and phosphate
    EP0282250A2 (en) * 1987-03-09 1988-09-14 American Colloid Company Liquid crop stimulant
    US5354350A (en) * 1993-12-14 1994-10-11 The Vigoro Corporation Citrate soluble slow release iron humate

    Cited By (5)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    EP1103535A3 (en) * 1999-11-24 2001-11-21 Iwao Takeda Fertilizer containing polyphosphate-metal chelates
    FR2803290A1 (en) * 1999-12-29 2001-07-06 Serge Allegre Production of a composition for correcting metal deficiencies in plants, e.g. chlorosis, comprises mixing an organic material with at least one metal salt and composting the mixture
    DE102005061117A1 (en) * 2005-12-19 2007-06-21 Tilco Biochemie Gmbh Preparation for soil improvement and fertilization
    EP3208254A1 (en) * 2016-02-17 2017-08-23 Fertinagro Nutrientes, S.L. Fertilizing composition which includes ions complexed with humic substances to improve the biological fixation of nitrogen by microorganisms present in the soil
    WO2017140926A1 (en) * 2016-02-17 2017-08-24 Fertinagro Nutrientes, S.L. Fertilizing composition which includes ions complexed with humic substances to improve the biological fixation of nitrogen by microorganisms present in the soil

    Also Published As

    Publication number Publication date
    IT1290913B1 (en) 1998-12-14
    HU9800188D0 (en) 1998-03-30
    ES2182256T3 (en) 2003-03-01
    EP0856502A3 (en) 1999-04-14
    US6080220A (en) 2000-06-27
    HUP9800188A2 (en) 1999-03-29
    ITRM970053A1 (en) 1998-08-03
    EP0856502B1 (en) 2002-09-04
    HUP9800188A3 (en) 1999-11-29

    Similar Documents

    Publication Publication Date Title
    EP0856502B1 (en) Stable form of iron humate or of other meso and micro nutritive elements available for plant nutrition and method for obtaining it
    US8795395B2 (en) Structurally modified lignite with or without extraction of functionally enhanced organic molecules
    CN104692937B (en) A kind of double chelating liquid fertilizer and preparation methods
    PT1612200E (en) Fertilising composition
    CN102164877A (en) Process for the preparation of fertilizer and surfactant natural compositions for washing, reclamation and cultivation of contaminated soils and related compositions
    WO2004110962A1 (en) Fertilizer compositions
    CN1508095B (en) Chelated plant micronutrients
    CN114890835A (en) Preparation method of modified poly-humic acid ammonium phosphate
    CN105130702A (en) Method used for preparing solid composite chelated water-soluble fertilizer containing humic acid from furfural residue
    Ray et al. Novel slow-releasing micronutrient fertilizers. 1. Zinc compounds
    RU2212391C2 (en) Method of composting organic and organomineral materials and wastes (options)
    Ogden et al. Elemental status of pine bark‐based potting media
    EP0205748A1 (en) Stable solutions of metal chelates, method for their preparation and their use as trace element fertilizers
    CN1223627A (en) Method of preparing base material of liquid fertilizer
    CN108383553A (en) A kind of fertilizer and the preparation method and application thereof containing middle trace element
    MXPA98000971A (en) Format of fumigate of iron or of other meso and nutritive microelements available for lanutrition of the plants and method for obtene
    CN1948235A (en) High content organic inorganic composite mixed fertilizer
    CN116813389A (en) All-element biochemical chelating liquid water-soluble fertilizer and preparation method thereof
    CA2090273A1 (en) Ammoniation of ground leonardite ore for dust suppression
    EP1680379A2 (en) Agents for solubilising metal ions
    CN114230392A (en) Production method of compound fertilizer
    IL307214A (en) Cocrystal fertilizers
    CN116063121A (en) Environment-friendly chelated element compound fertilizer and preparation method thereof
    US3107163A (en) Method of producing plants containing substantially no assimilated nickel ions
    Hodge et al. Solubility of metallic-salt in acid nutrients in acid fertilizer solutions of urea phosphate, urea sulfate and urea nitrate

    Legal Events

    Date Code Title Description
    PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

    Free format text: ORIGINAL CODE: 0009012

    AK Designated contracting states

    Kind code of ref document: A2

    Designated state(s): BE DK ES FI FR GB GR IT NL PT SE

    AX Request for extension of the european patent

    Free format text: AL;LT;LV;MK;RO;SI

    PUAL Search report despatched

    Free format text: ORIGINAL CODE: 0009013

    AK Designated contracting states

    Kind code of ref document: A3

    Designated state(s): AT BE CH DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

    AX Request for extension of the european patent

    Free format text: AL;LT;LV;MK;RO;SI

    17P Request for examination filed

    Effective date: 19990929

    AKX Designation fees paid

    Free format text: AT BE CH DE DK ES FI FR GB GR LI

    RBV Designated contracting states (corrected)

    Designated state(s): BE DK ES FI FR GB GR IT NL PT SE

    REG Reference to a national code

    Ref country code: DE

    Ref legal event code: 8566

    17Q First examination report despatched

    Effective date: 20000410

    GRAG Despatch of communication of intention to grant

    Free format text: ORIGINAL CODE: EPIDOS AGRA

    GRAG Despatch of communication of intention to grant

    Free format text: ORIGINAL CODE: EPIDOS AGRA

    GRAH Despatch of communication of intention to grant a patent

    Free format text: ORIGINAL CODE: EPIDOS IGRA

    GRAH Despatch of communication of intention to grant a patent

    Free format text: ORIGINAL CODE: EPIDOS IGRA

    GRAA (expected) grant

    Free format text: ORIGINAL CODE: 0009210

    AK Designated contracting states

    Kind code of ref document: B1

    Designated state(s): BE DK ES FI FR GB GR IT NL PT SE

    PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

    Ref country code: IT

    Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRE;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED.SCRIBED TIME-LIMIT

    Effective date: 20020904

    Ref country code: GR

    Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

    Effective date: 20020904

    Ref country code: FI

    Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

    Effective date: 20020904

    REG Reference to a national code

    Ref country code: GB

    Ref legal event code: FG4D

    PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

    Ref country code: SE

    Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

    Effective date: 20021204

    Ref country code: DK

    Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

    Effective date: 20021204

    PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

    Ref country code: PT

    Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

    Effective date: 20021213

    PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

    Ref country code: GB

    Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

    Effective date: 20030130

    REG Reference to a national code

    Ref country code: ES

    Ref legal event code: FG2A

    Ref document number: 2182256

    Country of ref document: ES

    Kind code of ref document: T3

    ET Fr: translation filed
    PLBE No opposition filed within time limit

    Free format text: ORIGINAL CODE: 0009261

    STAA Information on the status of an ep patent application or granted ep patent

    Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

    26N No opposition filed

    Effective date: 20030605

    GBPC Gb: european patent ceased through non-payment of renewal fee
    PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

    Ref country code: NL

    Payment date: 20060122

    Year of fee payment: 9

    PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

    Ref country code: FR

    Payment date: 20060125

    Year of fee payment: 9

    PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

    Ref country code: BE

    Payment date: 20060308

    Year of fee payment: 9

    NLV4 Nl: lapsed or anulled due to non-payment of the annual fee

    Effective date: 20070801

    REG Reference to a national code

    Ref country code: FR

    Ref legal event code: ST

    Effective date: 20070930

    BERE Be: lapsed

    Owner name: *VALAGRO S.P.A.

    Effective date: 20070131

    PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

    Ref country code: BE

    Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

    Effective date: 20070131

    PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

    Ref country code: NL

    Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

    Effective date: 20070801

    PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

    Ref country code: FR

    Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

    Effective date: 20070131

    PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

    Ref country code: ES

    Payment date: 20080218

    Year of fee payment: 11

    REG Reference to a national code

    Ref country code: ES

    Ref legal event code: FD2A

    Effective date: 20090131

    PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

    Ref country code: ES

    Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

    Effective date: 20090131